Readout and Control of a Power-Recycled Interferometric Gravitational-Wave Antenna
Interferometric gravitational-wave antennas are based on Michelson interferometers whose sensitivity to small differential length changes has been enhanced by the addition of multiple coupled optical resonators. The use of optical cavities is essential for reaching the required sensitivity but sets challenges for the control system, which must maintain the cavities near resonance. The goal for the strain sensitivity of the Laser Interferometer Gravitational-Wave Observatory (LIGO) is 10^-21 rms, integrated over a 100-Hz bandwidth centered at 150 Hz. We present the major design features of the LIGO length and frequency sensing and control system, which will hold the differential length to within 5 x10^-14 m of the operating point. We also highlight the restrictions imposed by couplings of noise into the gravitational-wave readout signal and the required immunity against them.
© 2001 Optical Society of America Received 6 October 2000. We thank our colleagues on the LIGO project who helped us with many useful suggestions and comments. In particular, we thank Jordan Camp for his early involvement in calculating the effects of light noise sources. This research was supported by National Science Foundation cooperative agreement PHY-9210038 and grant PHY-9870032.
Published - FRIao01.pdf